Surface features for locating net substrate buttons to enable self-piercing riveting (SPR) on brittle and low toughness materials

ABSTRACT

A method includes identifying a location of a locating feature disposed on an exterior profile of a lower substrate, the locating feature configured to identify a specified location of the exterior profile, positioning a self-piercing rivet along an upper substrate according to the identified location of the locating feature, and installing the self-piercing rivet through the upper substrate and into the lower substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.15/926,378, filed on Mar. 20, 2018, titled “SURFACE FEATURES FORLOCATING NET SUBSTRATE BUTTONS TO ENABLE SELF-PIERCING RIVETING (SPR) ONBRITTLE AND LOW TOUGHNESS MATERIALS”. The disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The present disclosure relates to the joining of various materials in anassembly, and more particularly to accurately installing fasteners suchas self-piercing rivets into workpieces/substrates of an assembly.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

As the automotive industry continues to focus on reducing the weight ofvehicles to meet customer expectations on fuel economy and CAFE(Corporate Average Fuel Economy) requirements, interest in alternativematerials including carbon fiber composite applications has increased.In body-in-white structures, joining methods have traditionally reliedon resistance-spot welding (e.g., in steel structures).

In the case of aluminum intensive vehicles and other mixed metal joiningapplications, self-piercing rivet technology prevails. One advantage ofself-piercing rivet technology is that it is a high production volumeassembly process. Self-piercing rivet technology is compatible withadhesive and both methods can be used together. The substrate materialmust be ductile enough to form a “button”, i.e., protrusion, which isthe result of creating the joint and the necessary deformation toprovide mechanical interlock.

Composite materials, such as carbon fiber, glass fiber or natural fibercomposites, can be limited in application due to challenges relating tojoining parts together. Frequently, these composites have limitedductility and are not well adapted to large displacements anddeformation required to join parts together with self-piercing rivets.Other non-composite materials having higher strength and light weightare also often brittle and challenging to join using self-piercing rivettechnology.

A challenge often faced with self-piercing rivet technology, however, isthat the location of a site for rivet installation may be difficult toidentify. This challenge is particularly exacerbated in high-volumeautomated production settings, in which it is desirable to make thejoint with little or no impact on cycle time and equipment.

The issue of accurately locating rivet installation sites to join avariety of materials, and particularly in a high-volume productionenvironment, is addressed by the present disclosure.

SUMMARY

In one form, a method of joining two substrates with a self-piercingrivet includes positioning an upper substrate, positioning a dimpledsubstrate adjacent to the upper substrate, the dimpled substrateincluding a preformed interior cavity, a preformed exterior profileadjacent the preformed interior cavity and defining a wall therebetween,and a locating feature configured to identify a location of the at leastone preformed exterior profile, identifying a location of the locatingfeature, positioning an installation tool adjacent to the locatingfeature, and installing the self-piercing rivet through the uppersubstrate and into the dimpled substrate.

In variations of the method, which may be implemented individually or incombination: the locating feature is selected from the group consistingof surface texturing, laser marking, laser projection, ink application,dimpling, chemical etching, a notch located on an edge of the dimpledsubstrate, a hole through the dimpled substrate adjacent to thepreformed exterior profile, an indent, a bead, and an embossment; thelocating feature is identified on an exterior portion of the dimpledsubstrate opposite the upper substrate; the locating feature is at leastone of: disposed on the preformed exterior profile, disposed adjacent tothe preformed exterior profile, and a notch formed into the dimpledsubstrate away from the preformed exterior profile; the locating featureis formed into or protruding out of the exterior portion of the dimpledsubstrate; the wall defines a variable thickness; identifying thelocation of the locating feature with a vision system; engaging aninsertion end of the self-piercing rivet with a bottom wall of thedimpled substrate.

In another form, a method of joining two substrates with a self-piercingrivet includes identifying a location of a locating feature disposed onan exterior profile of a lower substrate, the locating featureconfigured to identify a specified location of the exterior profile,positioning a self-piercing rivet along an upper substrate according tothe identified location of the locating feature, and installing theself-piercing rivet through the upper substrate and into the lowersubstrate.

In variations of the method, which may be implemented individually or incombination: positioning the upper substrate adjacent to the lowersubstrate; the locating feature is selected from the group consisting ofsurface texturing, laser marking, laser projection, ink application,dimpling, chemical etching, a notch located on an edge of the lowersubstrate, a hole through the lower substrate adjacent to the exteriorprofile, an indent, a bead, and an embossment; the lower substratefurther comprises an interior cavity, the exterior profile disposedadjacent the interior cavity and defining a wall therebetween; thelocating feature is identified on an exterior portion of the lowersubstrate opposite the upper substrate; the locating feature is at leastone of: disposed on the exterior profile, disposed adjacent to theexterior profile, and a notch formed into the lower substrate away fromthe exterior profile; the locating feature is formed into or protrudingout of the exterior portion of the lower substrate; the locating featureis formed into the lower substrate by at least one of stamping,mechanical surface texturing, laser marking, laser projection, inkapplication, and chemical etching.

In another form, a method includes inserting a self-piercing rivet to aninstallation tool, positioning an upper substrate and a dimpledsubstrate adjacent to each other, the dimpled substrate including apreformed exterior profile defining a preformed interior cavity and alocating feature disposed on the dimpled substrate and configured toidentify a location of the preformed exterior profile, identifying alocation of the locating feature on the dimpled substrate, positioningthe installation tool above the upper substrate based on the location ofthe locating feature, and actuating the installation tool to pierce theupper substrate with an insertion end of the self-piercing rivet and tomove the insertion end into the preformed interior cavity of the dimpledsubstrate.

In variations of the method, which may be implemented individually or incombination: the locating feature is selected from the group consistingof surface texturing, laser marking, laser projection, ink application,dimpling, chemical etching, a notch located on an edge of the dimpledsubstrate, a hole through the dimpled substrate adjacent to thepreformed exterior profile, an indent, a bead, and an embossment; thepreformed exterior profile includes a peripheral wall and a bottom wall,the performed interior cavity defined between the peripheral wall andthe bottom wall, and the method further comprises engaging the insertionend of the self-piercing rivet to the bottom wall; the locating featureis formed into or protruding out of the exterior portion of the dimpledsubstrate.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now bedescribed various forms thereof, given by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of an assembly having a self-piercingrivet (SPR) installed therein and constructed according to the presentdisclosure;

FIG. 2 is a cross-sectional view of a dimpled substrate from FIG. 1constructed in accordance with the teachings of the present disclosure;

FIGS. 2A-2C are bottom views of a dimpled substrate having a locatingfeature on a bottom surface of a button according to the presentdisclosure;

FIGS. 3A-3C are bottom views of a dimpled substrate having a locatingfeature next to a button according to the present disclosure;

FIGS. 4A-4C are bottom views of a dimpled substrate having a locatingfeature notched into the lower substrate according to the presentdisclosure;

FIG. 5 is a flow chart illustrating a method of locating a feature forinstallation of a self-piercing rivet according to the presentdisclosure; and

FIG. 6 is a cross-sectional view of an upper substrate and a dimpledsubstrate with a self-piercing rivet tool positioned to drive aself-piercing rivet into the upper substrate and the dimpled substrate.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

Referring to FIGS. 1 and 2 , a dimpled substrate 20 for use in anassembly 100 having substrates joined by a self-piercing riveting (SPR)method is illustrated. Generally, the assembly 100 includes an uppersubstrate 110, the dimpled substrate 20, and a self-piercing rivet 120.Installation of self-piercing rivets 120 is described in greater detailin U.S. Pat. No. 9,828,040, which is commonly owned with the presentapplication and the contents of which are incorporated herein byreference in their entirety.

The dimpled substrate 20 defines at least one preformed exterior profile21 in the form of a button shaped protrusion or “button” 22. The button22 extends downwardly from a lower surface 24 of the dimpled substrate20 and is disposed in a predetermined location where a correspondingself-piercing rivet is to be inserted into the dimpled substrate 22, asdescribed in greater detail below. The dimpled substrate 20 may be acast part, a molded part, or a 3D-printed part, among others. In variousforms of the present disclosure, the dimpled substrate 20 is an aluminumcasting, an aluminum extrusion, or a composite material. It should beunderstood that these materials and methods of forming are merelyexemplary and should not be construed as limiting the scope of thepresent disclosure.

The button 22 of the dimpled substrate 20 in this form is generally anopen cylindrical shape having a peripheral wall 26 and a bottom wall 28.The exterior surfaces of the peripheral wall 26 and the bottom wall 28together define the preformed exterior profile 21 as shown. The dimpledsubstrate 20 also includes a preformed interior cavity 30. The preformedinterior cavity 30 is configured to receive a fastening system, such asthe self-piercing rivet 120, which may or may not be plasticallydeformed after installation, as described in greater detail below.

In one form, the bottom wall 28 of the button 22 may define a variablethickness as shown. Details regarding the variable thickness of thebottom wall 28, among other features of the dimpled substrate 20, isshown and described in U.S. patent application Ser. No. 15/726,172,which is commonly owned with the present application, and the contentsof which are incorporated herein by reference in its entirety.

Referring to FIGS. 2A-4C, the dimpled substrate 20 further includes atleast one locating feature 32 configured to identify a location of thepreformed exterior profile 21, and also the button 22 and its interiorcavity 30, for more accurate location of the self-piercing rivet 120during installation. Generally, the locating feature 32 may be on ornear the preformed exterior profile 21 to identify the location forinstallation of the self-piercing rivet 120. The locating feature 32 maybe a physical material applied to the dimpled substrate 20, a physicalfeature formed into or on the dimpled substrate 20, or an opticalprojection onto the dimpled substrate 20, among others. Examples of eachof these forms of a locating feature 32 are provided in greater detailbelow but should not be construed as limiting the scope of the presentdisclosure. The inventors have discovered that many forms of providingthe locating feature 32 can be realized in a variety of methods and thusthe various forms illustrated and described herein are merely exemplaryand should not be construed as limiting the scope of the presentdisclosure

In FIGS. 2A-2C, the locating feature 32 is disposed on a bottom surface34 of the bottom wall 28 of the preformed exterior profile 21 accordingto one form of the present disclosure. The locating feature 32 may bemade in an initial manufacturing process step when the dimpled substrate20 is formed, such as for example during casting or in a stamping die.More specifically, the locating feature 32 may be stamped into thebottom surface 34, causing limited plastic deformation of the materialof the dimpled substrate 20 in order to create a location that can bedetected my manual, optical, or other automated methods as set forthbelow. The locating feature 32 may take the form of those shown, or anynumber of geometrical shapes such as a dimple, an indent, a bead, or anembossment. Alternatively, the locating feature 32 may be applied duringa post process step after the button 22 is formed, such as by way ofexample mechanical surface texturing, laser marking, laser projection(no modification of button or application of any additional material),ink application/stamping, or chemical etching, among others.

Referring specifically to FIG. 2A, the locating feature defines a cross32 a comprising two intersecting lines generally perpendicular to eachother, which can be detected by a vision system 33, for example. Oncethe locating feature 32 a is detected, the location of the preformedexterior profile 21, and also the button 22 and its interior cavity 30,is identified to accurately position an installation tool above thedimpled substrate 20, as described in further detail below. Although thelocating feature 32 a is illustrated as a cross-shaped feature, thepresent disclosure is not limited to a cross 32 a and other geometricalfigures or shapes may be employed while remaining within the scope ofthe present disclosure.

Referring to FIG. 2B, a locating feature 32 b is in the form of surfacetexturing in a predetermined area along the preformed exterior profile21 of the button 22. The surface texturing 32 b can be detected by avision system 33 or other automated or mechanical means to identify thelocation of the preformed exterior profile 21, and hence the button 22and its interior cavity 30.

Referring to FIG. 2C, instead of the locating feature 32 being made inan initial processing step, the locating feature 32 c is formed in apost-processing step, such as for example an additional stampingprocess, laser marking, laser projection, or ink application, amongothers. In this example, after the dimpled substrate 20 is formed, anink applicator is used to apply a marking, which in this form is anothercross-shaped feature. The locating feature 32 c is then detected by anauxiliary system, such a vision system 33 or other manual or automatedmethods to determine the location of the preformed exterior profile 21,and hence the button 22 and its interior cavity 30 for more accurateinstallation of the self-piercing rivet 120.

Referring to FIGS. 3A-3C, the locating feature 32′, according to anotherform of the present disclosure is illustrated in which the locatingfeature 32 a′, 32 b′, and 32 c′ are disposed adjacent to, instead ofdirectly on, the preformed exterior profile 21 on the lower surface 24of the dimpled substrate 20. In this form, the locating feature 32 andthe button 22 are preferably formed in the same processing step in orderto maintain proper tolerances on the location of the button 22 from onebutton 22 to another.

In some instances, providing a locating feature on or near the button 22is not desired due to a subsequent manufacturing step that may mask thelocating feature, such as, for example, a coating step. Therefore, asillustrated in FIGS. 4A-4C, the present disclosure provides a locatingfeature in the form of a notch 32″ formed into the dimpled substrate 20away from the button 22. The notch 32″ is shown as being formed on anedge 62 of the dimpled substrate 20, however, should not be construed aslimiting the present disclosure and thus the notch 32″ may be formed inany location about the dimpled substrate 20 that allows the locatingfeature to be detected after subsequent manufacturing steps such ascoating have been completed. The notch 32″ may define any geometricshape that allows the notch 32″ to be detected, such as rectangular(FIG. 4A), oval (FIG. 4B), and triangular (FIG. 4C). Just as thelocating feature 32′ disposed adjacent to the button 22 discussed above,it is desired to create the notch 32″ and the button 22 simultaneouslyin order to maintain proper tolerances on locations of the notches 32″from button 22 to button 22.

Referring to FIG. 5 , a method 90 of locating a feature for installationof a self-piercing rivet is provided by the present disclosure. At step92, an upper substrate is positioned and a dimpled substrate ispositioned adjacent to the upper substrate, the dimpled substratecomprises at least one preformed interior cavity, at least one preformedexterior profile adjacent to the interior cavity and defining a walltherebetween, and at least one locating feature configured to identify alocation of the preformed exterior profile. At step 94, a location ofthe preformed exterior profile of the dimpled substrate is accuratelydetermined by identifying a location of the locating feature. Thus, atstep 96, accurate positioning of an installation tool having at leastone self-piercing rivet above the preformed interior cavity of thedimpled substrate is accomplished. At step 98, the self-piercing rivetis installed through the upper substrate and into the dimpled substrate.

As best shown in FIG. 6 , to join the dimpled substrate 20 to the uppersubstrate 110, the upper substrate 110 is positioned adjacent to or overthe dimpled substrate 20 in a self-piercing rivet tool 80. Theself-piercing rivet 120 is placed inside the self-piercing rivet tool 80and a location of the locating feature 32 is identified by an auxiliarysystem such as a vision system 33 (FIGS. 2A-4C), or other mechanical orautomated system. Once the locating feature 32 is identified, theself-piercing rivet tool 80 is positioned adjacent to the locatingfeature 32. In other words, the self-piercing rivet 120 is placed insidethe self-piercing rivet tool 80 and immediately above the preformedinterior cavity 30 of the dimpled substrate 20 based on the identifiedlocation of the locating feature 32.

As further shown, the self-piercing rivet 120 has an insertion end 88 topierce through the upper substrate 110 and to be inserted into thepreformed interior cavity 30 of the dimpled substrate 20 to engage thebottom wall 28 of the button 22. It should be understood that thedimpled substrate 20 and the upper substrate 110 may be arranged in anyorientation while still remaining within the scope of the presentdisclosure.

Because the locating feature allows for accurately identifying thelocation of the preformed button, the self-piercing riveting tool can bepositioned such that the self-piercing rivet can be installed directlyinto the preformed interior cavity of the dimpled substrate whilemaintaining proper tolerances. Thus, accurate joining of brittlematerial or low-strain material to other materials using self-piercingrivet technology in a high volume automated production setting isaccomplished with little or no impact on cycle time and equipment. Itshould also be understood that the locating feature of the presentdisclosure may be used in any application which requires joining of twoor more layers of materials.

The description of the disclosure is merely exemplary in nature and,thus, variations that do not depart from the substance of the disclosureare intended to be within the scope of the disclosure. Such variationsare not to be regarded as a departure from the spirit and scope of thedisclosure.

What is claimed is:
 1. A method of joining two substrates with aself-piercing rivet, the method comprising: positioning an uppersubstrate; positioning a dimpled substrate adjacent to the uppersubstrate so that an upper surface of the dimpled substrate faces towardthe upper substrate and a lower surface faces away from the uppersubstrate, the dimpled substrate comprising: a preformed interior cavitydefined in the upper surface of the dimpled substrate; a preformedexterior profile extending from the lower surface of the dimpledsubstrate, the preformed exterior profile being adjacent the preformedinterior cavity and defining a wall therebetween; and a locating featureconfigured to identify a location of the at least one preformed exteriorprofile and visible when the dimpled substrate is positioned adiacent tothe upper substrate; identifying a location of the locating featureusing an automated vision system; positioning an installation tooladjacent to the locating feature; and installing the self-piercing rivetthrough the upper substrate and into the dimpled substrate.
 2. Themethod of claim 1, wherein the locating feature is selected from thegroup consisting of surface texturing, laser marking, laser projection,ink application, dimpling, chemical etching, a notch located on an edgeof the dimpled substrate, a hole through the dimpled substrate adjacentto the preformed exterior profile, an indent, a bead, and an embossment.3. The method of claim 1, wherein the locating feature is identified onan exterior portion of the dimpled substrate opposite the uppersubstrate.
 4. The method of claim 3, wherein the locating feature is atleast one of: disposed on the preformed exterior profile, disposedadjacent to the preformed exterior profile, and a notch formed into thedimpled substrate away from the preformed exterior profile.
 5. Themethod of claim 1, wherein the locating feature is formed into orprotruding out of the exterior portion of the dimpled substrate.
 6. Themethod of claim 1, wherein the wall defines a variable thickness.
 7. Themethod of claim 1, further comprising engaging an insertion end of theself-piercing rivet with a bottom wall of the dimpled substrate.
 8. Amethod of joining two substrates with a self-piercing rivet, the methodcomprising: identifying, via an automated vision system, a location of alocating feature disposed on a lower substrate, the lower substrateincluding an exterior profile, the locating feature configured toidentify a specified location of the exterior profile; positioning aself-piercing rivet along an upper substrate according to the identifiedlocation of the locating feature; and installing the self-piercing rivetthrough the upper substrate and into the lower substrate.
 9. The methodof claim 8, further comprising positioning the upper substrate adjacentto the lower substrate.
 10. The method of claim 8, wherein the locatingfeature is selected from the group consisting of surface texturing,laser marking, laser projection, ink application, dimpling, chemicaletching, a notch located on an edge of the lower substrate, a holethrough the lower substrate adjacent to the exterior profile, an indent,a bead, and an embossment.
 11. The method of claim 8, wherein the lowersubstrate further comprises an interior cavity, the exterior profiledisposed adjacent the interior cavity and defining a wall therebetween.12. The method of claim 8, wherein the locating feature is identified onan exterior portion of the lower substrate opposite the upper substrate.13. The method of claim 12, wherein the locating feature is at least oneof: disposed on the exterior profile, disposed adjacent to the exteriorprofile, and a notch formed into the lower substrate away from theexterior profile.
 14. The method of claim 8, wherein the locatingfeature is formed into or protruding out of the exterior portion of thelower substrate.
 15. The method of claim 8, wherein the locating featureis formed into the lower substrate by at least one of stamping,mechanical surface texturing, laser marking, laser projection, inkapplication, and chemical etching.
 16. A method for joining twosubstrates, the method comprising: inserting a self-piercing rivet to aninstallation tool; positioning an upper substrate and a dimpledsubstrate adjacent to each other so that an upper surface of the dimpledsubstrate opposes the upper substrate and a lower surface of the dimpledsubstrate faces away from the upper substrate, the dimpled substratecomprising: a preformed exterior profile that extends away from theupper substrate and defines a preformed interior cavity open toward theupper substrate; and a locating feature disposed on the dimpledsubstrate and configured to identify a location of the preformedexterior profile and visible when the dimpled substrate is positionedadjacent to the upper substrate; identifying, with an automated visionsystem, a location of the locating feature on the dimpled substrate;positioning the installation tool above the upper substrate based on thelocation of the locating feature; and actuating the installation tool topierce the upper substrate with an insertion end of the self-piercingrivet and to move the insertion end into the preformed interior cavityof the dimpled substrate.
 17. The method of claim 16, wherein thelocating feature is selected from the group consisting of surfacetexturing, laser marking, laser projection, ink application, dimpling,chemical etching, a notch located on an edge of the dimpled substrate, ahole through the dimpled substrate adjacent to the preformed exteriorprofile, an indent, a bead, and an embossment.
 18. The method of claim16, wherein the preformed exterior profile includes a peripheral walland a bottom wall, the performed interior cavity defined between theperipheral wall and the bottom wall, and the method further comprisesengaging the insertion end of the self-piercing rivet to the bottomwall.
 19. The method of claim 16, wherein the locating feature is formedinto or protruding out of the exterior portion of the dimpled substrate.